I am in it for the site. I can tell you why some of that is happening to you.

1. the value in your account is tied to the actual monetary value of the steem currency. So as the value of steem fluctuates (just like bitcoin, gold silver, us dollar, etc) the value of your steem in your wallet fluctuates. This also impacts vote value before the payout. Not really under their control that is a market thing.

2. As to not enough power. You start with 100% voting power... everytime you vote that % drops. It regenerates over time. So if you vote a lot that % will get low. You can check your power by looking at your profile. Normally you look at https://steemit.com/@kingsjack123 change the steemit.com part to steemd.com and you get a different site that shows you some details you normally don't see including your current voting %. Your steem power is currently 3. Your voting power is 98% though so I'd expect you to be able to vote. I am not a developer by the way. Just a user but I really like steemit.com as you post people will vote on your comments (replying to other people helps too) and you'll get more than 3 pretty quickly.